The three cross pattern is just fine and, as you can see, the spoke crossed over the first two and under the third. This is called weaving(so what).

Do not purchase alloy nipples! Ensure that you get brass ones. They are far stronger. Also, have you checked out the price of spokes at your local bike shop? Where I live I can get a complete set(72 spokes and nipples - always get extra nipples thrown in since nipple quality control is not what is should be) for under thirty five dollars. Just a thought.